Structural beam

ABSTRACT

A fabricated structural beam ( 1 ), including a longitudinally extending top plate having a pair of longitudinally extending opposite edge regions ( 4 ), and a longitudinally extending cylindrical bottom tube ( 6 ) spaced from and extending parallel with the top plate ( 3 ) equidistant from the edge regions ( 4 ) of the top plate ( 3 ). A web plate ( 13 ) of generally V shape in transverse cross section provides a pair of web portions ( 12 ) and a bend portion  14  between the web portions ( 12 ). The bend portion ( 14 ) extends about the bottom tube ( 6 ) so that the bottom tube ( 6 ) nests along the web plate ( 13 ), and the web plate ( 13 ) is connected to the bottom tube ( 6 ) along opposite side regions ( 11 ) thereof. The web portions ( 12 ) extend one from each side of the bottom tube ( 6 ) to the top plate ( 3 ). Each web portion ( 12 ) has a longitudinally extending connection region connected along the top plate ( 3 ) adjacent a respective edge region ( 4 ) of the top plate ( 3 ). The beam ( 1 ) tapers in lateral extent from the top plate ( 3 ) to the bottom tube ( 6 ).  
     A torsion beam crane ( 100 ) incorporating the structural beam ( 1 ) as a bridge beam is also disclosed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates generally to a structural beam, and in particular, to a fabricated metal structural beam. The beam is applicable for use as a bridge beam or girder of a travelling torsion beam crane, and will be disclosed in relation to that application. It should be appreciated, however, that the invention is not limited to that application.

[0003] 2. Description of the Prior Art

[0004] Torsion beam cranes typically include a bridge beam or girder for spanning a load working area, and a bogie connected at each end of the beam for mounting the crane on rails for travel along those rails over the load working area. A trolley is mounted on the beam for movement therealong. The trolley is located at the top of the beam and is cantilevered therefrom so as to carry a hoist adjacent one side of the beam. In use, the hoist is connectable to a load for lifting and moving by the crane.

[0005] One known type of bridge beam is of a generally elongate box-shape. The beam is fabricated from metal plate and provides spaced apart top and bottom plates interconnected by spaced apart side or web plates. In one form of crane, the top plate has longitudinally extending edge flanges projecting laterally outwardly from the web plates and providing running surfaces engaged by wheels of the trolley and along which those wheels roll in order to move the trolley along the beam. In a torsion beam crane, those surfaces are located on respective upper and lower faces of the edge flanges so as to act to retain the cantilevered trolley on the beam.

[0006] Placement of the hoist close to the beam is desirable to improve the crane load lifting capacity. However, with a crane having a box-shaped beam it may not be possible to lift the hoist hook unit beyond the bottom plate because of interference between he beam, and hook unit and/or supported load. As a result, the usable hook height (the height hook unit can be raised without interference above he working area floor) is compromised. Whilst increasing the lateral spacing between the hoist and beam can provide increased clearance for the hook unit, and so improve useable hook height, that in turn reduces the lifting capacity of the crane.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide a structural beam suitable for use as a crane bridge beam or girder of a torsion beam crane, and which will improve useable hook height of the crane without compromising lifting capacity.

[0008] A further object of the present invention is provide a structural beam of relatively simple fabricated construction.

[0009] With these objects in mind, the present invention provides in one aspect a fabricated structural beam including: a longitudinally extending first member; a longitudinally extending second member spaced from the first member; and, at least one web member interconnecting the first and second members, wherein the beam has a narrower lateral extent at the second member than at the first member.

[0010] Preferably, the beam has a lateral extent which narrows from the first member to the second member. In one preferred form, the beam tapers in lateral extent from the first member to the second member. Preferably, the first member is a plate member and the second member is a tube member. Preferably, the tube member extends parallel, and in spaced relation, to a plane of the plate member. The tube member is preferably laterally narrower than the plate member thereby providing the beam with the narrower lateral extent. The plate member and tube member preferably each have a central longitudinal axis. Those axes lie in a common plane extending transverse of the plate member.

[0011] In one preferred form, the tube member has a cylindrical cross sectional shape.

[0012] Preferably, a pair of web members are provided. Those web members preferably extend along and between the first and second members in spaced apart relation to one another. Preferably, the first member has a pair of longitudinally extending opposite edge regions, and each web member has a longitudinally extending connection region connected along the first member adjacent a respective edge region thereof. In one preferred form, the web members are connected to the first member laterally inwardly of the edge regions so that the edge regions project laterally outwardly of the web members. Preferably, the second member has a pair of longitudinally extending opposite side regions, and each web member has a longitudinally extending connection region connected along the second member at respective side regions thereof.

[0013] In one preferred form, the web members are formed from a unitary web plate. That web plate is preferably shaped to extend outwardly about the second member with spaced apart portions of the web plate extending from the second member to the first member and forming the web members. The web plate has longitudinal edge regions providing the connection regions connected along the first member. The web plate also has a longitudinally extending transitional region between the web plate portions providing the connection regions connected along the second member.

[0014] According to a further aspect of the present invention, there is provided a torsion beam crane, including: a bridge beam for spanning a load working area, the bridge beam having a longitudinally extending top plate with a pair of longitudinally extending opposite edge regions, a longitudinally extending bottom tube spaced from and extending parallel with the top plate, and at least one side web interconnecting the top plate and bottom tube, wherein the beam has a narrower lateral extent at the bottom tube than at the top plate; a trolley mounted on the beam for movement therealong, the trolley being located adjacent the top plate and cantilevered from one side of the beam; and, a hoist carried by the trolley so as to be positioned to the one side of the beam, the hoist including a hook unit which can be raised and lowered during operation of the hoist, the narrower lateral extent of the beam adjacent the bottom tube member providing a clearance space to the one side of the beam to enable raising of the hook unit into a position adjacent the one side of the beam.

[0015] Preferably, the trolley has wheels engaging the longitudinally extending edge regions of the top plate so as to mount the trolley for movement along the top plate. In one preferred form, the longitudinally extending edge regions project laterally outwardly of the web member and provides opposed running surfaces for the wheels of the trolley.

[0016] Preferably, the crane includes a bogie connected at each end of the bridge beam for mounting the crane on rails for travel along the rails over the load working area.

DESCRIPTION OF THE DRAWINGS

[0017] The following description refers to preferred embodiments of the structural beam and a travelling torsion beam crane incorporating the structural beam of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the beam and crane are illustrated. It is to be understood that the invention is not limited to the embodiments a hereinafter described and as illustrated.

[0018] In the drawings, where the same reference numerals identify the same or like components:

[0019]FIG. 1 is a perspective view of a structural beam according to one preferred embodiment of the present invention;

[0020]FIG. 2 is a cross-sectional view of the structural beam of FIG. 1;

[0021]FIG. 3 is a cross-sectional view of a structural beam according to another preferred embodiment of the present invention;

[0022]FIG. 4 is a perspective view of a travelling torsion beam crane incorporating the structural beam of FIGS. 1 and 2; and

[0023]FIG. 5 is a cross-sectional view of the crane of FIG. 4 taken through Section V-V.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0024] Referring initially to FIGS. 1 to 3 of the drawings, there is generally shown two variations of a structural beam 1 suitable for use as a bridge beam of a travelling torsion beam crane.

[0025] The beam 1 includes a longitudinally extending planar first member 2. First member 2 is provided by a top plate 3 having a pair of longitudinally extending opposite edge regions 4.

[0026] The beam 1 also includes a longitudinally extending tubular second member 5. Second member 5 is provided by a bottom tube 6 which is spaced apart below, and extends parallel to, the top plate 3. The bottom tube 6 is positioned relative to the top plate 3 between the edge regions 4 and, in these embodiments, approximately midway between or equidistant from those regions 4. Thus, as shown, a central longitudinal axis x₁ of the top plate 3 and a central longitudinal axis x₂ of the bottom tube 6 lie in a common plate y of the beam 1 extending transverse of the top plate 3. That plane y coincides with a central longitudinal plane of the beam 1.

[0027] It should be appreciated that in alternative embodiments, the bottom tube 6 may be positioned toward one of the edge regions 4 of the top plate 3, and thus offset from the central longitudinal axis x₁.

[0028] In these embodiments, the bottom tube 6 has a cylindrical shape in transverse cross section. It will be appreciated that other shapes may be suitable, for example obround or elliptical. The diameter of the bottom tube 6 is small compared with the width of the top plate 3 so as to provide a narrowing of the beam 1 between the top and bottom thereof, as will be explained in more detail hereinafter.

[0029] A pair of web members 7 interconnect the first and second members 7 are provided by side webs 8 extending between the top plate 3 and the bottom tube 6 in spaced apart relation. As shown, the side webs 8 extend generally symmetrically of the central longitudinal plane y. It will be appreciated, however, that in other embodiments those side webs 8 may extend asymmetrically of the central plane y such as where the bottom tube 6 is offset from that plane y.

[0030] The side webs 8 are at least generally planar. Moreover, those webs 8 extend continuously between and along the top plate 3 and bottom tube 6. Thus, the beam 1 is of a hollow configuration, and generally triangular shape in transverse cross section.

[0031] Each side web 8 has longitudinally extending connection regions 9,10 at which the web 8 is respectively connected to the top plate 3 and the bottom tube 6. The regions 9 connect at or adjacent the edge regions 4 of the top plate 3. As shown, those connection regions 9, connect adjacent the edge regions 4 so that the edge regions 4 project laterally outwardly from the side webs 8. The edge regions 4 may project the same distance (as shown) or different distances (not shown) from the connection regions 9, in alternative embodiments.

[0032] The connection regions 10 connect to the bottom tube 6 at or adjacent longitudinally extending opposite side regions 11 of the bottom tube 6. In the case of a cylindrical bottom tube 6, the connection is at diametrically opposite side regions of the tube 6.

[0033] The side webs 8 are comprised of web portions 12 of a unitary web plate 13 bent or otherwise deformed so as to extend about the bottom tube 6. The plate 13 is curved so as to fit about the cylindrical bottom tube 6 in surface-to-surface engagement. Thus, the bottom tube 6 is nested or cradled within a bend portion 14 of the web plate 13 connecting the web portions 12 of that plate 13.

[0034] The connection regions 9 connecting the side webs 8 to the top plate 3 are provided by opposite longitudinal edge regions of the web plate 13, whilst the connection regions 10 connecting with side webs 8 to the bottom tube 6 are provided by transitional regions 15 between the bend portion 14 and web portions 12 of the web plate 13.

[0035] The side webs 8 are connected to the top plate 3 and bottom tube 6 by welding. That welding is achieved with full penetration V-butt welds at joints between the plate 3, tube 6 and webs 8. In addition, spaced apart plug welds may be provided between the bend portion 14 of the web plate 13 and the bottom tube 6.

[0036] In these embodiments, the beam 1 is composed of metal, such as steel, plate and tube stock.

[0037] The beam 1 may be constructed in any size having regard to its intended application. In use as a bridge beam of a travelling torsion beam crane, one suitable beam (as shown in FIGS. 1 and 2) provides a top plate 3 of about 600 mm wide and 16 mm thick, a bottom tube 6 of about 170 mm outside diameter and 4.8 mm or 6.4 mm wall thickness, and a web plate 13 of about 1500 mm wide and 6 mm thick. The beam 1 so constructed has an overall height of about 70 mm. Other beams suitable for use as a bridge beam include one (as shown in FIG. 3) constructed of a narrower top plate 3 and a wider web plate 13 so that the beam 1 will have a narrower but deeper cross sectional shape.

[0038] Referring now to FIGS. 4 and 5, the beam 1 is shown in use as a substitute for a conventional box-shaped bridge beam or girder in a travelling torsion beam crane 100. The crane 100 includes beam 1 acting as a bridge beam for spanning a load working area. A bogie 101 is connected at each end of the beam 1 for mounting the crane 100 on rails (not shown) for travel along those rails over the load working area.

[0039] A trolley 102 is mounted on the beam 1 for movement therealong between the bogies 101. The trolley 102 is located adjacent the top of the beam 1, and has a mounting frame 103 extending over the top plate 3 and a support frame 104 centilevered from one side of the beam 1.

[0040] A load lifting hoist 105 is carried by the trolley 102. The hoist 105 is mounted on the support frame 104 so as to be positioned to the one side of the beam 1.

[0041] The hoist 105 includes a hook unit 106 which can be raised and lowered during operation of the hoist in order to raise and lower a load connected thereto. As particularly shown in FIG. 5, because of the angled side webs 8 and relatively narrow bottom of the beam 1, a clearance space S is provided to the side of the beam 1 adjacent the hoist 105. That clearance space S is sufficient to easily accommodate the crane hook unit 106 in a fully raised position adjacent the support frame 104. As a result, the hook unit 106 does not interfere with the beam 1 as it is raised beyond the bottom of the beam 1. When compared with a crane having a conventional box-shaped bridge beam of equivalent lifting capacity, useable hook height in hoist 105 is increased by about 300 mm by virtue of the beam 1.

[0042] The beam is of simple construction, formed from stock materials using conventional fabrication techniques. As such, manufacture of the beam is likely to be both easy and inexpensive.

[0043] Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of the beam previously described without departing from the ambit of the invention. 

1. A fabricated structural beam, comprising: a longitudinally extending first member; a longitudinally extending second member spaced from the first member; and, at least one web member interconnecting the first and second members, wherein the beam has a narrower lateral extent at the second member than at the first member.
 2. A beam as claimed in claim 1 , wherein the beam has a lateral extent which narrows from the first member to the second member.
 3. A beam as claimed in claim 1 , wherein the beam tapers in lateral extent from the first member to the second member.
 4. A beam as claimed in claim 1 , wherein the first member is a plate member.
 5. A beam as claimed in claim 1 , wherein the second member is a tube member.
 6. A beam as claimed in claim 1 , wherein the first member is a plate member and the second member is a tube member, and the tube member extends parallel, and in spaced relation, to a plane of the plate member.
 7. A beam as claimed in claim 6 , wherein the tube member is laterally narrower than the plate member thereby providing the beam with the narrower lateral extent.
 8. A beam as claimed in claim 6 , wherein the plate member and tube member each have a central longitudinal axis, and the axes lie in a common plane extending transverse of the plate member.
 9. A beam as claimed in claim 5 , wherein the tube member has a cylindrical cross sectional shape.
 10. A beam as claimed in claim 1 , wherein a pair of web members are provided, extending along and between the first and second members in spaced apart relation to one another.
 11. A beam as claimed in claim 10 , wherein the first member has a pair of longitudinally extending opposite edge regions, and each web member has a longitudinally extending connection region connected along the first member adjacent a respective edge region thereof.
 12. A beam as claimed in claim 11 , wherein the web members are connected to the first member laterally inwardly of the edge regions so that the edge regions project laterally outwardly of the web members.
 13. A beam as claimed in claim 10 , wherein the second member has a pair of longitudinally extending opposite side regions, and each web member has a longitudinally extending connection region connected along the second member at respective side regions thereof.
 14. A beam as claimed in claim 10 , wherein the first member has a pair of longitudinally extending opposite edge portions, the second member has a pair of longitudinally extending opposite side regions, and the web members are formed from a unitary web plate shaped to extend outwardly about the second member with spaced apart portions of the web plate extending from the second member to the first member, the web plate having longitudinally extending edge regions connected along the first member adjacent the respective edge regions thereof, and longitudinally extending transitional regions between the web plate portions connected along the second member at the side regions thereof.
 15. A beam as claimed in claim 10 , wherein the web members are connected to the first and second members by welding.
 16. A beam as claimed in claim 1 , wherein the beam is of generally triangular shape in transverse cross section, the first member providing one side of that shape, the second member providing an apex of that shape, and the web member providing the remaining sides of that shape.
 17. A fabricated structural beam, comprising: a longitudinally extending top plate having a pair of longitudinally extending opposite edge regions; a longitudinally extending cylindrical bottom tube, the bottom tube being spaced from and extending parallel with the top plate equidistant from the edge regions of the top plate; and, a web plate of generally V shape in transverse cross section, the web plate providing a pair of web portions and a bend portion between the web portions, the bend portion extending about the bottom tube so that the bottom tube nests along the web plate, the web plate being connected to the bottom tube along opposite side regions thereof, and the web portions extending one from each side of the bottom tube to the top plate, each web portion having a longitudinally extending connection region connected along the top plate adjacent a respective edge region of the top plate, wherein the beam tapers in lateral extent from the top plate to the bottom tube.
 18. A torsion beam crane, comprising: a bridge beam for spanning a load working area, the bridge beam having a longitudinally extending top plate with a pair of longitudinally extending opposite edge regions, a longitudinally extending bottom tube spaced from and extending parallel with the top plate, and at least one side web interconnecting the top plate and bottom tube, wherein the beam has a narrower lateral extent at the bottom tube than at the top plate; a trolley mounted on the beam for movement therealong, the trolley being located adjacent the top plate and cantilevered from one side of the beam; and, a hoist carried by the trolley so as to be positioned to the one side of the beam, the hoist including a hook unit which can be raised and lowered relative to the trolley during operation of the hoist, the narrower lateral extent of the beam adjacent the bottom tube member providing a clearance space to the one side of the beam to enable raising of the hook unit into a position adjacent the one side of the beam during use of the crane.
 19. A torsion beam crane as claimed in claim 18 , wherein the trolley has wheels engaging the longitudinally extending edge regions of the top plate so as to mount the trolley for movement along the top plate.
 20. A torsion beam crane as claimed in claim 19 , wherein the longitudinally extending edge regions project laterally outwardly of the web member and provides opposed running surfaces for the wheels of the trolley.
 21. A torsion beam crane as claimed in claim 18 , and including a bogie connected at each end of the bridge beam for mounting the crane on rails for travel along the rails over the load working area.
 22. In a torsion crane, comprising: a bridge beam for spanning a load working area, the bridge beam having a longitudinally extending top plate; a trolley mounted on the top plate for movement therealong, and being cantilevered from one side of the beam; and a hoist carried by the trolley so as to be positioned to the one side of the beam, the hoist including a hook unit which can be raised and lowered relative to the trolley during operation of the hoist; the improvement comprising: the bridge beam having a longitudinally extending bottom tube spaced from and extending parallel with the top plate, and at leat one side web interconnecting the top plate and bottom tube, wherein the beam has a narrower lateral extent at the bottom tube than at the top plate to provide a clearance space to the one side of the beam to enable raising of the hook unit into the clearance space to the one side of the beam. 